Lamp-locking construction



E. H. FREEMAN.

LAMP LOCKING CONSTRUCTION.

APPLICATION FILED JULY 2.1918.

1,326,924, Patented Jn. 6,1920.

E060@ h" FEffw www UNITED STATES PATENT OFFICE.

EDGAR H. FREEMAN, OE TRENTON, NEW JERs-Efassrenon. To E. H. FREEMAN ELECTRIC COMPANY, A CORPORATION or NEW JERSEY.

LAMP-'LCCKTNG CONSTRUCTION.

Speoicaton of Letters Patent.

Patented vJ an. 6, 1920.

Application led July 2, 1918. Serial No. 243,008.

To all whom t may concern:

Be it known that I, EDGAR H. FREEMAN, citizen of the United States, residin at Trenton, in the county of Mercer and tate oi New Jersey, have invented certain new and useful Improvements in Lamp-Locking Constructions, of which the following is a speciiication.

This innvention relates to a novel and practical lamp locking construction t'or ei- 'ectually locking electrical lamps in their sockets or' receptacles.

To this end the invention contemplates a socket construction involving means for securely locking the plug oi' a lamp therein` thereby preventing theft or removal by unauthorized persons, or the removal of the lamp a suliicient distance to draw it away from its center plug contact to thereby open the circuit. In this connection it is proposed to provide a locking mechanism which is entirely concealed, and s'o embodied in the socket construction, that it is in effect a part thereof, whereby in order to destroy the locking means for the lamp it would be necessary to destroy the entire socket.

A further object of the invention is to provide a lamp locking construction which though protected against unauthorized agencies may nevertheless be readily manipn ulated by authorized persons to lock and unlock the lamp without injury to the lamp or' other part of the device.

A further object of the invention is to provide a construction of the character referred to which is simple, practical, and reliable, and susceptible of embodiment in any of the well known forms or types of electrical lamp sockets. A more general object of the invention is to provide a lamp locking device which may be readily incorporated in the construction of an electrical fitting such as socketsv and electrical receptacles adapted to carry the ordinary electrical mp- With the above and other objects in view the invention consists in the novel construction, combination and arrangement of parts hereinafter more fully pointed out, illustrated and claimed.

A preferred and practical embodiment of the invention is shown in the accompanying drawings, in which Figure l' is" atop' plan 'View' of an all-porcelain type of socket having the present invention embodied therein.

Fig. 2 is a vertical sectional view taken on the line A-A of Fig. l.

Fig. 3l is another cross section taken on the line B-B of Fig. l.

Fig. 4 is a detail elevation of the screw shell portion of the socket and the shiftable clamping bolt of the locking construction.

Fig. 5 is a detail perspective view of the lockingpost and snubbing coil which grips the lamp plug.

Fig. 6 is a detail perspective view of the locking bolt.

Similar reference characters designate corresponding parts throughout the several tigures of the drawings.

As previously indicated, the present invention may be carried out in connection with various types or forms ot electrical lamp holders. However, for the purpose of illustration, there is shown in the drawings, a lamp receptacleo't the all-porcelain type, which preferably includes an attaching. base 1, and the socket portion`2 for receiving the screw plug oit the incandescent lamp. This socket portion 2, while oit' a generally circular formation, is provided' at one side with an offset angular` portion 3 which forms a housing chamber 4 for" the operating parts of the lamp locking means, and has in one of its side walls a key-hole opening 5, for the purpose to be explained. l

The metal fittings for the receptacle or socket, may be, and preferably are, conven tional and according to the usual practice. Moreover, the present invention includes as one of its important and practical features the use of the screw shell contact as a support and guide for the main locking inember .of the device as will presently appear. Accordingly, the socket 2, accommodates therein both `lamp terminals, namely, the center plug contact 6 connected with one binding contact 6 and the screw shell contact 7 connected with the other wire binding terminal 7a.

As indicated the screw contact shell 7 corn-v bines with the locking device to readily engage and lock the plugr of the lamp in the socket. Therefore, to this end, it is proposed to employwithin the mouth of the screw shell contact a plug locking member which is preferab'lyin they form of a helieally coiled spring wire, which is so arranged and disposed in the screw shell that under the vmanipulation of the operating parts housed within the chamber 4, the same will have the effect of a snubbing coil on the lamp plug to thereby securely lock the plug in the socket.

Referring to this snubbing coil which is designated generally as 8 it will be observed that the same consists of a relatively few but spaced convolutions, the same being of a suiiicient number however to give a iirm frictional clamping engagement on the entire circumference of the plug, and when in position the said convolutions seat themselves in the valleys of the threads of the screw shell to thus Qermit of the free insertion of the lamp p ug. One end of the socalled snubbing or locking coil 8 is preferably rigidly secured to the interior of the shell 7 as indicated at 9, Fig. 3, by soldering or otherwise while the other end is adapted to project into a suitable transverse slot 10 formed in a locking post designated generally as 11 and arranged within the housing chamber 4 of the socket exterior. It will lthus be apparent that one end of the coil 8 is held fast and rigid to the shell while the other end is relatively free, whereby under the manipulation of the operating mechanism, presently to be described, it may be contracted and expanded to effect the locking and the removal of the lamp in the socket. An important feature in connection with the foregoing is that the screw shell contact which acts to hold the convolutions of the coil in a proper spaced relation, thereby prevents the convolutions of the coil kicking out of their proper spiral planes, and thus permits a proper threading in and out -of the lamp plug. At the same time, being only secured at its innermost end, the threads of the screw shell contact do not interfere with the free contraction and expansion of each individual coil throughout its entire extent.

The locking post 11 above referred to is preferably in the form of an angular plate having` the transverse slot 10 in one wall while the opposite wall is provided with a locking bolt opening 12. One end of the post is also formed with an offset holding portion 13 which is adapted to be held in place by one of the screws for a binding terminal, as is clearly shown in Fig. 2, while the upper end of the post 111 is benty over to provide a substantially closed end wall for sealing the entire housing chamber 4E, which will prevent tampering with the means for manipulating the snubbing coil. As will be readily observed from Fig. l, the locking poet 11 which occupies a rigid and fixed location inthe socket readily accommodates within its angle portion a suitable shiftable locking nut of angular form, the same being designated generally as 15 and having the flange thereof disposed adjacent the slot 10 adapted to receive the free end of the snubbing coil S, while the opposite flange of the nut is provided with a screw threaded opening 16 for receiving an operating bolt or screw 17 which has a loose fit in the opening 12 of the post 11.

The locking bolt or screw 17 is clearly shown in Fig. 6 of the drawings and preferably consists of a threaded shank portion for engaging the threaded opening 16 of the nut 15, and a special head portion 18 having formed therein a suitable transverse slot 19 and a centrally projecting piny Q0, whereby the complemental parts 20a of a key K may be readily engaged therewith to give the same the necessary rotary movement to cause the shifting of the nut 15. For the purpose of preventing the operation ofthe screw 17 with unauthorized tools or keys, the

`head thereof is preferably protected by a suitable housing cup 21, clearly shown in Figs. 1 `and l of the drawings.

YWith the arrangement described, it will be apparent that since one end of the coil S is rigidly held within the screw contact 7 and the free end thereof is connected with the shiftable nut element 15, the movement of the latter through the operation of the screw 17 will readily cause the contraction or expansion of all of the convolutions of the coil, according to the direction of rotation of the screw. The normal condition of parts is shown in Fig. 1, wherein the snubbing coil is expanded as much as the screw shell will permit, and the movable end of the said coil 8 occupies a position at one end of the slot 10. `When the screw 17 is turned to the right by means of the key, it will have the effect of bringing the nut element 15 forwardly as indicated by dotted lines in Fig. 1 which will thus contract or reduce the diameter of the coil and thus cause the same to have an extremely tight binding or locking engagement with the plug of the lamp which maybe inserted therein.

It will now be apparent that the present arrangement provides a simple and effective locking mechanism which may be readily manipulated by authorized persons, and which is relatively small and easy to make and assemble, thus presenting practical advantages which greatly enhance the commercial value of the invention. Furthermore, by utilizing the coil 8 in the manner described any desired pressure may be placed upon the plug of the lamp without danger of breaking or rupturing any part of the lamp so that if it is desired to remove the same, it may be still available for further use.

I claim:

1. A lamp locking device comprising, in combination with the socket member, a helical snubbing coil arranged within the socket member, a coil holder and guide within the socket member, and a key actuated operating device operatively engaging the coil to contract and expand the same.

2. A lamp locking device comprising, in combination with the socket member, a helical snubbing coil arranged within the socket member, a screw shell contact located within the socket member and constituting a holder and guide for the snubbing coil,.and a key actuated operating. device operatively engaging the coil to contract and expand the same.

3. A lamp locking device comprising, in combination with the socket member, a helical snubbing coil arranged within the socket member, a screw shell contact located Within the socket member and constituting a holder and guide for the snubbing coil, and a key actuated operating device operatively connected with one end of the coil to contract and expand the same.

el. A lamp locking device comprising, in combination with the socket member, a helical snubbing coil arranged within the mouth of the socket member, a coil holder and guide within the socket member, and a key actuated operating device engaging with one end of the coil only to contract and expand the same.

5. A lamp locking construction for electrical lamp sockets including in combination with the screw shell contact of the socket, of a convoluted spring member arranged in the mouth of said shell and having` one end fastened therein While the other end is free, and a device for Inoving the free end of said member, said device consisting of a fixed slotted post for receiving the free endof the spring, a shiftable nut element, and a rotatable screw loosely abutting against said post and having a threaded engagement with said shiftable nut element.

6. A lamp locking construction for electrical lampy sockets including in combination a socket body having a housing chamber at one side of the socket portion thereof, and a key-hole opening in the wall of said housing chamber, a screw shell contact within the socket of the body, a contractible coiled locking element arranged within the mouth of the screw shell contact, an operating device for said locking element arranged within the housing and including a key-operated locking screw and a shiftable nut engaged with said locking element.

7. A lamp locking construction for electri'cal lamp sockets including in combination a socket body having a housing chamber at one side of the socket portion thereof, and a key-hole openingin the wall of said housing chamber, a screw shelllcontact within the socket of the body, a contractible coiled locking element arranged within the mouth of the screw shell contact, an operating device for said locking element including a keeper post having one end thereof bent over to form a seal. for the housing chamber, and means also carried by said post for manipulating the locking element.

In testimony whereof I hereunto affix my signature in the presence of two witnesses.

EDGAR H. FREEMAN. Witnesses ADA MARSH, ANNIE A. HENRY. 

